american troops as at its peak at 150,000. the final deployment, for some, is the first deployment in a nine-year war. what is their mission? our correspondent went to find out. >> the 101st airborne are on the move. this regiment served in normandy, vietnam's, and now afghanistan. they said their goodbyes in kentucky at fort campbell. they are the last of 30,000 american troops arriving here. they hope to finish off the taliban and end this war. these new infantrymen seemed un daunted. >> i realize we're in a hostile environment, but we are still around the same leadership, you know?